#计算100以内的和
# num = 1
# sum = 0
# while num <= 100:
#     sum+=num
#     num+=1
# print(sum)
#计算阶乘
# a = int(input("请输入一个整数:"))
# t = 1
# while a:
#     t *= a
#     a-=1
# print(t)
#计算 1 - a的阶乘和
# a = int(input('请输入一个整数:'))
# t = 1
# sum = 0
# b = 1
# while b <= a:
#     t *= b
#     sum += t
#     b += 1
# print(sum)
